Setyr worked example — LOCO-4412 Locomotive — Traction Motor and HEP Isolation Not approved for use. Version 1 · 2026-09-25
Worked example only — your site must author, review and approve its own
procedure under 29 CFR 1910.147(c)(4). setyr.com/procedures
LOCO-4412 Locomotive — Traction Motor and HEP Isolation
Rail
Traction motor change on a road locomotive in the shop. Covers main generator excitation, head-end power at 480V, the battery bank that cannot be switched off, and movement restraint on a vehicle that is itself the hazard.
This is a worked example, not a procedure you can adopt. It describes equipment that does not exist, with illustrative tag numbers.
29 CFR 1910.147(c)(4) requires the employer to develop, document and
utilise energy control procedures specific to their own machines, and (c)(6)
requires the employer to inspect those procedures periodically. Neither duty
can be delegated to a vendor or discharged by this document.
Isolation points
| # | Tag (illustrative) | Type | Disposition | What it does and why | Dwell |
|---|---|---|---|---|---|
| 10 | LOCO-4412-CHOCK | Block | Apply & verify | Wheel chocks and derail on the shop track. Caution: The derail protects the crew under the locomotive from a movement elsewhere on the track. It is not optional because the shop is quiet. Chock both sides of one axle and set the derail at the shop track entrance. Must be ENGAGED. | — |
| 20 | LOCO-4412-HANDBRK | Block | Apply & verify | Locomotive hand brake, applied on the truck being worked. Caution: Bleeding main reservoir air releases the air brakes. The hand brake becomes the only restraint on a vehicle on shop track. Apply the hand brake fully and confirm the chain is tight. Must remain APPLIED. | — |
| 30 | LOCO-4412-ENG | Switch | Isolate & lock | Prime mover engine start control and fuel rack, isolated at the engine control switch. Caution: A locomotive has two control stands. Isolating at one does not disable the other. Place the engine control switch to ISOLATE and lock. Confirm the engine cannot be cranked from either control stand. | — |
| 40 | LOCO-4412-GEN-FLD | Breaker | Isolate & lock | Main generator field excitation breaker. Caution: A rotating generator with residual field produces voltage at the traction motor even with the throttle at idle. Open and lock the field breaker. Prove no excitation at the generator terminals. | — |
| 50 | LOCO-4412-TM-DISC | Disconnect | Isolate & lock | Traction motor cutout switch for the motor being changed. Caution: Cutting out a motor at the switch does not de-energise the common DC bus it shares with the others. Open the cutout, lock, and prove dead at the motor leads in the traction motor junction box. | — |
| 60 | LOCO-4412-DC-LINK | Bleed | Isolate & lock | Traction converter DC link capacitor bank. Caution: The DC link holds a lethal charge long after the engine is shut down. Time alone is not the verification; the meter reading is. Allow the DC link to discharge for the full time, then confirm below the safe threshold with an approved meter before opening the converter cabinet. | 600s |
| 70 | LOCO-4412-HEP | Breaker | Isolate & lock | Head-end power contactor and 480V trainline supply to the coaches. Caution: HEP can be supplied from the adjacent locomotive through the trainline. Isolating this unit does not de-energise the trainline. Open the HEP contactor, lock, and prove dead at the trainline receptacle. | — |
| 80 | LOCO-4412-SHORE | Disconnect | Isolate & lock | Shore power connection at the shop stand. Caution: Shore power backfeeds the auxiliary bus and keeps cab systems live with the engine shut down. Disconnect shore power and lock the shop stand receptacle. | — |
| 90 | LOCO-4412-BATT | Switch | Isolate & lock | 64V battery bank knife switch in the electrical locker. Caution: The battery cannot be drained or removed for the job. It is the supply that stays live when everything else is isolated. Open the battery knife switch and lock. Confirm control voltage is absent at the relay panel. | — |
| 100 | LOCO-4412-AIR | Valve | Isolate & lock | Main reservoir air, 140 psi, supplying brakes, sanders and the horn. Caution: Stored main reservoir air operates the independent brake and the sanders without any electrical supply. Close the main reservoir cutout and bleed the reservoir to zero at the drain. | 300s |
| 110 | LOCO-4412-JACK | Block | KEEP ENERGISED | Shop jacks or drop table supporting the locomotive during traction motor removal. Caution: Isolating the shop jack supply mid-lift strands the locomotive part-supported. Do NOT isolate. Confirm all four jacks are rated, synchronised and bearing before the truck is rolled out. | — |
| 120 | LOCO-4412-SHOPLT | Breaker | KEEP ENERGISED | Pit lighting and ventilation under the shop track. Caution: Traction motor work happens from the pit. Isolating pit services to lock the locomotive puts the crew in the dark. Do NOT isolate. Confirm pit lighting and extraction are running before anyone enters the pit. | — |
What your site must supply
- Your own asset and isolation-point tag numbers. The tags shown are illustrative and refer to equipment that does not exist.
- The actual location of every disconnect, valve and vent on your equipment.
- Measured stored-energy magnitudes and the dwell time required to dissipate them.
- Your verification method for each point, and who is authorised to perform it.
- Any additional energy sources present on your equipment and absent here.
Authorship and validation
This example was authored by Setyr for domain validation. It is not derived from any customer's controlled documents. It illustrates the elements 29 CFR 1910.147(c)(4)(ii) requires a procedure to contain — it does not certify compliance, which is a property of an employer's programme rather than of any document.